As computational resources become increasingly affordable, improvements in health care technology will become limited by the capacity to interface new imaging methodologies with human physiology. We have proven the technology for a dry, capacitance-coupled, skin sensor that assesses the electrical activity of the brain when it is placed against the scalp. When integrated with the Geodesic Sensor Net, the dry sensor yields excellent EEG recordings. In year 1 of the Phase II research, we will implement a 128 channel EEG system based on the Phase I results, including discrete-component active sensors, injection-molded sensor pedestals, the Geodesic Sensor Net tension structure, and software and hardware controls to integrate with EGI's digitial EEG system. This system will begin immediate testing in research and clinical EEG laboratories. In year 2, the second-generation system will implement a microfabricated (chip) design that provides dynamic impedance- matching, current injection (for scanning impedance tomography), and circuitry for integration of power, EEG, and digital configuration controls on a single wire. The ability to measure brain activity quickly, easily and inexpensively with this new technology will revolutionize the study of brain electrical activity in research and clinical practice. PROPOSED COMMERCIAL APPLICATION The inadequate spatial sampling of conventional EEG is becoming increasingly clear. Dense array EEG is limited by electrode application methods. Coupled by new advances in analytic software, the active sensor system could place powerful new analytic tools in the hands of clinical electroencephalographers.